In one type of peristaltic pump, a flexible tube is compressed between rollers that are carried by a rotor and travel along a circular path and a race that has a surface adjacent to and concentric with the path of the rollers. As the occluded portion of the tube is advanced, the fluid in front of it is forced to travel through the tube.
A use of such a pump is in extracorporeal blood treatment. The peristaltic pumps have been provided on the front panel of a blood processing machine, employing flexible tube portions of a disposable tubing set that is changed for use with a different donor/patient. Some tubing sets have included cartridges that are removably mounted on the machine and carry flexible tubes in position to be acted upon by pump rollers on the front panel of the machine, e.g., DeVries U.S. Pat. No. 4,379,452; published European Patent Application 0,134,436; Heath et al., U.S. Ser. No. 748,545, filed June 25, 1985; and Finsterwald et al., U.S. Ser. No. 860,539, filed May 7, 1986.
In the Finsterwald et al. '539 patent application, there is description of a pump that self-loads a flexible tube portion placed in a tube mounting region adjacent to a tube pumping region between the race and the rollers, as the rollers rotate, owing to the action of a small diameter roller portion adjacent to the tube mounting region and a large diameter roller portion adjacent to the tube pumping region. When unloading the tube from the pump, a lifter arm extending from a movable cover lifts the tube out of the tube pumping region as the cover is moved away from the pump.